Emergency Power Based on Cordless Drill Batteries

[Don Eduardo] took matters into his own hands after experiencing a days-long power outage at his house. And like most of us have done at least one, he managed to burn his fingers on a regulator in the process. That’s because he prototyped a way to use power tool batteries as an emergency source — basing his circuit on a 7812 linear regulator which got piping hot in no time flat.

His next autodidactic undertaking carried him into the realm of switch-mode buck converters (learn a bit about these if unfamiliar). The device steps down the ~18V output to 12V regulated for devices meant for automotive or marine. We really like see the different solutions he came up with for interfacing with the batteries which have a U-shaped prong with contacts on opposite sides.

The final iteration, which is pictured above, builds a house of cards on top of the buck converter. After regulating down to 12V he feeds the output into a “cigarette-lighter” style inverter to boost back to 110V AC. The hardware is housed inside of a scrapped charger for the batteries, with the appropriate 3-prong socket hanging out the back. We think it’s a nice touch to include LED feedback for the battery level.

We would like to hear your thoughts on this technique. Is there a better way that’s as easy and adaptive (you don’t have to alter the devices you’re powering) as this one?

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CNC Plotter Uses Only the Good DVD Drive Parts

It wasn’t that long ago that wanting to own your own 3D printer meant learning as much as you possibly could about CNC machines and then boostrapping your first printer. Now you can borrow time on one pretty easily, and somewhat affordably buy your own. If you take either of these routes you don’t need to know much about CNC, but why not use the tool to learn? This is what [Wootin24] did when building a 3D printed plotter with DVD drive parts.

Plotters made from scrapped floppy, optical drives, and printers are a popular hand, and well worth a weekend of your time. This one, however, is quite a bit different. [Wootin24] used the drives to source just the important parts for CNC precision: the rods, motors, motors, and bearings. The difference is that he designed and 3D printed his own mounting brackets rather than making do with what the optical drive parts are attached to.

This guide focuses on the gantries and the mechanics that drive them… it’s up to you to supply the motor drivers and electrical side of things. He suggests RAMPS but admins he used a simple motor driver and Arduino since they were handy.

Solar Tetroon Spooks Albuquerque

An interesting take on Hackerspace outreach is spooking the local community into calling the FAA and even the Air Force. It wasn’t exactly the plan at Quelab, but after an experimental solar tetroon got away from [Gonner Menning], one of the space’s members, that’s exactly what happened.

This is the first we remember hearing of solar tetroons. A tetroon is actually a fairly common weather balloon design using four triangle-shaped pieces. The solar part is pretty neat, it’s a balloon that uses the sun to heat air inside of a balloon. Instead of filling the bladder with a lighter-than-air gas it is filled with regular air and the sun’s rays heat it to become lighter than the surrounding ambient air.

For this particular flight the balloon was never supposed to be off the tether. Previous iterations had turned out to be rather poor fliers. Of course it figures that when [Gonner] finally tuned the design with an optimal weight to lift ratio it slipped its leash and got away. The GPS package tracked it for quite a while but ended up dying and the craft was nary to be found.

We weren’t going to embed the local news coverage video, but at the end the talking heads end up rolling around the word “Hackerspace” in their mouths like it’s foreign food. Good for a giggle after the break.

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Passion Project Turns BeagleBone into Standalone Super NES

So you want to play some retro games on your BeagleBone, just load up Linux and start your favorite emulator right? Not if you’re serious about it. [Andrew Henderson] started down this path with the BeagleBoard-xM (predecessor of the BeagleBone Black) and discovered that the performance with Snes9X wasn’t quite what he had in mind. He got the itch and created a full-blown distro called BeagleSNES which includes bootloader and kernel hacks for better peformance, a custom GUI, and is in the process of developing hardware for the embedded gaming rig. Check out the documentation that goes along with the project (PDF); it’s a blueprint for how open source project guides should be presented!

The hardware he’s currently working on is a Cape (what add-on boards for the BBB are called) that adds connectors for original Nintendo and Super Nintendo controllers. It also includes an RTC which will stand in for the real-time clock features included in some cartridges (Pokemon Yellow). Also in the works is a 3D printed enclosure which would turn it into a portable, something like this other BBB portable hack.

Check out a demo of what BeagleSNES can do in the video after the break.

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Cracking Weather Station Checksum

[BaronVonSchnowzer] is spinning up some home automation and settled on an inexpensive ambient temperature sensor which is sold to augment the data a home weather station collects. He found that the RF protocol had been reverse engineered and will use this information to harvest data from a sensor in each room. In true hacker fashion, he rolled his own advances out to the Internet so that others may benefit. Specifically, he reverse engineered the checksum used by the Ambient F007TH.

He got onto this track after trying out the Arduino sketch written to receive the sensor’s RF communications. One peculiar part of the code turned out to be a filter for corrupt messages as the protocol’s checksum hadn’t yet been worked out. Figuring out how the checksum byte owrks wasn’t an easy process. The adventure led him to dump 13k samples into a spreadsheet to see if sorting similar sets of 5-byte message and 1-byte checksum would shed some light on the situation. The rest of the story is some impressive pattern matching that led to the final algorithm. Now [BaronVonSchnowzer] and anyone else using these modules can filter out corrupt data in the most efficient way possible.

Finding an Active TX Pin on Cheap GPS

Twenty Euros will score you a small, self-contained GPS keychain. Crack that case open and you can have a lot more. [j3tstream] explored the guts of the thing and found that the NMEA data can be streamed out of the TX pin on the GPS chip.

First off, check out that miniscule GPS antenna module, crazy! But we digress. For testing purposes the asynchronous UART of the GPS was probed, proving that the data can be acquired. From there [j3tstream] moved to an Arduino Pro Mini with an SD card for data logging. The uC is powered from the GPS board but this will quickly exhaust the stock battery so [j3tstream] swapped it out for one from an old cellphone.

That little dot-matix LCD that comes with the unit also caught our eye. If you can hack a headless interface for the GPS that could be repurposed for your next project. May we suggest a wearable gaming project for it?

Casing up the Teensy SDR

[Rich, VE3MKC] has made a lot of progress on his Software Defined Radio (SDR) which is based on a Teensy. His latest update shows off the hardware in an enclosure and a few new features.

When we looked at this in April of last year it was pretty much a proof-of-concept with components hanging loose from jumper wires. The new case mounts everything securely in a plastic Hammond enclosure with copper clad for the front and rear panels. The SoftRock SDR unit was yanked from its case and retrofitted with connectors to make it swappable for other units.

A little help goes a long way and [Rich] thanks his friend [Loftur, VE2LJX] for contributing numerous code improvements and feature additions which can be viewed in the repository. Check out the video below where these features are shown off.

In its present state the radio draws 80 mA at 12V in receive mode. It doesn’t transmit yet but we’ll keep our eyes open for another update on that. [Rich] plans to populate the input circuitry and write the transmit code next.

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